Sealing a closed entryway against the leakage of water has long been a problem for designers of such entryways. The problem is particularly acute in a blowing rain storm, where the wind can easily blow rain water between a closed door and the jamb or threshold of the entryway. One common location for such leakage to occur is at the bottom corners of the door where the vertical jambs of the entryway meet the threshold cap of the sill assembly. This is because water tends to collect in these corners during a blowing rain storm and can be blown between the lower corners of the door and the jamb and into the building. While modern weather stripping seals well around most of the periphery of the door, it has nevertheless not proven effective at the bottom corners of the door where the weather stripping spans the space between the bottom of the door and the door sill assembly. Accordingly, there exists a need for a method and apparatus for providing a watertight seal at the bottom corners of an entryway door when the door is closed. It is to the provision of such a method and apparatus that the present invention is primarily directed.